A Brief Introduction to Textile Processing - AGOA Export Toolkit

that can force dye through hundreds of layers of yarn wrapped tightly around the cone, but this
method generally produces fewer tangling problems.
Whether
dyed in skein or cone form, each batch of yarn dyed together is referred to a dyelot. While
color should be uniform within a single dyelot, there is often a discernable difference in color
between dyelots. For quality control is it vital to segregate dyelots so only one is used in a single
garment, helping ensure that within the garment, yarn (hence fabric) color will be uniform.
Fabric.
Dyeing and / or printing fabric allows the greatest design flexibility but varying levels of
colorfastness, depending upon the dyes and methods used. It also requires that substantial quantities
of fabric be dyed or printed the same color or pattern to be cost effective. As with yarn dyeing, each
batch of fabric dyed becomes an individual dyelot. With fabric, individual dyelots should also be
segregated at the apparel manufacturing stage to help avoid color – related problems in the finished
garment.
Modern
technology and computers are allowing designers to print only select areas of a fabric,
depending upon the shape of the garment to be made from the fabric, effectively eliminating a split
in the printed pattern where fabric is seamed. To date, however, this remains more a laboratory
experiment than a commercially viable printing method. (For greater detail on fabric dyeing and
printing, see Fabric dyeing and printing section below.)
Garment.
Last, fully - constructed garments can be garment - dyed, allowing retailers to wait until
the last point in the manufacturing chain to make decisions on the number of garments to produce in
each color, thereby reducing the risk of unsold inventory from bad color decisions. With garment
dyeing, however, more highly specialized equipment is required, the entire garment must be dyed the
same color, threads must accept dye in the same way as base fabric or off quality results, and it may
be more difficult or impossible to do certain additional types of fabric processing normally done after
dyeing or printing many apparel fabrics.
F abric dyeing and printing
Because
of its complexity, fabric dyeing and printing will be described in greater detail here than
other stages at which color may be imparted.
Dyeing.
Dyeing is the process of giving color to a fabric, one color at a time. With dyeing, the entire
length of fabric is exposed to the dye solution (called, in industry, dye liquor). In dyeing, the entire
fabric is placed in the dye solution, causing most or all the fabric to take a single color. (By contrast,
in printing, color is placed onto one side of the fabric in selected patterns.) Certain dyeing techniques
(such as resist dyeing in which parts of a fabric are tied or waxed to prevent the dye solution from
penetrating the cloth) may prevent dye from fully reaching selected parts of the fabric, however these
methods are generally more suitable to artisanal operations than industrial application, and they do
not fully prevent dye uptake. The “crackled” look of batik fabrics results from some dye penetrating
where there are cracks in the wax used to resist dye or prevent it from reaching the fabric.
Industrially,
fabrics may be dyed in batch form or in a continuous process. In the former, certain lengths of
fabric will be dyed at one time, generally in a large machine similar to a clothes washing machine.
More common at the industrial scale, however, is continuous processing, whereby lengths of fabric
are stitched together temporarily so one continuous length of fabric runs through sequential
processing equipment, including a series of troughs containing the dye liquor, allowing greater
processing efficiency.
Prepared by Margaret Bishop and Brent Smith for the West Africa Trade Hub 8/04 11